OCP Natural Join Question

According to the answer key, B, D, and F are correct. I am trying to figure out how ON or USING could be used with a natural join to limit the join conditions. Neither of the 2 statements shown below, where I try and limit the NJ columns, According to the answer key, B, D, and F are correct. I am trying to figure out how ON or USING could be used with a natural join to limit the join conditions. Neither of the 2 statements shown below are valid.

I'd appreciate some input.

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Oracle9i provides an ON clause and a USING clause to assist in defining join conditions.

Which three statements regarding the use of these clauses are true? (Choose three.)

1. A USING clause can be used with LOBs.
2. Subqueries can be used in the join predicate of an ON clause.
3. An ON clause must be specified when performing a natural join.
4. Multiple ON clauses can be used and are evaluated in the order listed.
5. A USING clause can implement either an equijoin or a non-equijoin condition.
6. A USING clause can be used with a natural join to limit the columns for the join condition.
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create table pay_check(empno number, pay_date date,net_amount number);

create table pay_earnings(empno number, pay_date date,earn_amount number);

select empno
from pay_check

       natural join
       pay_earnings
       using (empno);

select empno
from pay_check c

       natural join
       pay_earnings e
       on (c.empno = e.empno);

are valid. Received on Sun Mar 23 2003 - 12:55:40 CST